Questions to consider pre-installation

Q: Will an air source heat pump installation improve my EPC rating? Will the value of my house improve?

An EPC ( Energy Performance Certificate ) rating reflects a home's carbon footprint. It can be improved through the installation of various energy efficiency upgrades, such as insulation. Generally speaking, having an ASHP installed is seen as being an advantage when it comes to improving efficiency ratings. Alongside other measures like double glazing and solar panel installations, ASHPs are becoming a value enhancement, key to a property’s selling price on the market. EPC and carbon footprint explained: • Energy Performance Certificate (EPC): A certificate required for selling or renting a property, graded A (best) to G (worst) on energy efficiency and environmental impact. • Carbon Footprint: The total amount of greenhouse gases (like CO2) produced by a home's energy use for heating, lighting, and power. How EPCs Relate to CO2 Emissions • Direct Correlation: A higher EPC rating directly means lower predicted CO2 emissions, as the assessment considers energy use for heating, lighting, and hot water. • Rating Bands: Each jump up in the A-G scale represents a significant reduction in CO2, with each band potentially cutting emissions by 30-40% on a diminishing scale. • Example: An EPC B-rated house might emit around 2 tonnes of CO2 annually, while a similar house with a D rating could emit about 4 tonnes.

Q: Does my house need to have solar or battery for air source heat pump effectiveness?

It’s not a requirement for your home to have solar panels or batteries for your heat pump to work, however combining it with these technologies may lead to better energy efficiency, bringing down your environmental impact and leading to lower running costs.

Question 1

Is the cylinder noisy?

Accepted Answer

Hot water cylinders are designed to be fairly quiet. However, they are not silent. A cylinder will make some noise occasionally as a normal part of its operation, however if it’s constantly hissing or banging, then there may be an issue to look at. Most of the issues that occur with a cylinder can be prevented by proper installation, servicing, and maintenance.

Question 2

Why is it important to have space around the air source heat pump? How much space should I leave?

Accepted Answer

There should be enough space around your heat pump to allow air to flow unobstructed across the outside unit and be drawn in effectively. Having clear space around the heat pump is also important for access during maintenance and servicing. Though they are quiet units, clear space around a heat pump also minimises noise disruption further by preventing vibration against walls or windows.

Generally speaking, you should leave around one metre around the fan of your heat pump and 50cm on the sides and the rear of the outside unit, but this is only a rough guidance.

Question 3

What is heat loss? How is it calculated?

Accepted Answer

A heat loss calculation is carried out using specialist software as part of the installation process. It is used to work out the heating needs of your property and the heat pump’s suitability. It is essential for working out your heat pump’s efficiency and gives an idea of the running costs.

Heat loss calculations are worked out by measuring the effectiveness of your insulation, taking into account factors such as the dimensions of each room and how often the temperature changes inside and outside of your property. This is why no two calculations are ever the same.

Question 4

Will an air source heat pump installation improve my EPC rating? Will the value of my house improve?

Accepted Answer

An EPC (Energy Performance Certificate) rating reflects a home's carbon footprint. It can be improved through the installation of various energy efficiency upgrades, such as insulation.

Generally speaking, having an ASHP installed is seen as being an advantage when it comes to improving efficiency ratings. Alongside other measures like double glazing and solar panel installations, ASHPs are becoming a value enhancement, key to a property’s selling price on the market.

EPC and carbon footprint explained:

• Energy Performance Certificate (EPC): A certificate required for selling or renting a property, graded A (best) to G (worst) on energy efficiency and environmental impact.
• Carbon Footprint: The total amount of greenhouse gases (like CO2) produced by a home's energy use for heating, lighting, and power.

How EPCs Relate to CO2 Emissions

• Direct Correlation: A higher EPC rating directly means lower predicted CO2 emissions, as the assessment considers energy use for heating, lighting, and hot water.
• Rating Bands: Each jump up in the A-G scale represents a significant reduction in CO2, with each band potentially cutting emissions by 30-40% on a diminishing scale.
• Example: An EPC B-rated house might emit around 2 tonnes of CO2 annually, while a similar house with a D rating could emit about 4 tonnes.

Question 5

I have a 3 bed house. Is an air source heat pump suitable for me?

Accepted Answer

An air source heat pump can work well for a three-bedroom property. Your installer will take various factors into account, including the home’s insulation, the layout and size of rooms, and even the local climate.

It is important to remember that heat pumps have different heating output capabilities. Understanding your home’s heat loss ensures that you have the right size heat pump based on your energy demands and your home’s characteristics.

Typically, UK homes need between 6 – 8 kW systems to provide a comfortable level of warmth, depending on the size of the property and its insulation, alongside other factors.

Question 6

Do I need to change my radiators when having an air source heat pump fitted?

Accepted Answer

Most installations can connect to existing pipework, with resized emitters where needed, to suit the lower flow temperatures that heat pumps operate at.

Question 7

How can I calculate how much I’ll save on my energy bills?

Accepted Answer

Getting an idea of how much money you could save with an air source heat pump can be worked out by comparing your current heating cost with the annual electricity cost of the ASHP, using its SCOP efficiency.

Determine Current Costs:
Start by checking your past bills to learn what your current annual heating consumption is, in kilowatts (kWh), and multiplying it by your unit price (£0.25/kWh for example).

Estimate ASHP Consumption:
Then, to get an estimation for the annual operating cost of your ASHP, divide the figure you worked out for your old heating cost by the Seasonal Coefficient of Performance (SCOP) figure of your ASHP to get a figure for the energy you need for comfort throughout the course of a year.

Calculate New Operating Cost:
Multiply your ASHP electricity usage figure by its unit rate to work out the final figure for your ASHP’s annual running cost.

Calculate Savings:
For your annual savings estimate, simply subtract the ASHP operating figure you just calculated from your current annual heating cost. Work out your payback period getting your total installation costs, minus any grants or discounts like the Boiler Upgrade Scheme, and divide that total by your annual savings total.

Annual Savings = (Current Annual Heating Cost) - (Estimated New ASHP Operating Cost)

It’s worth noting some important factors that will impact your savings and payback figure. For example, a higher SCOP figure will mean lower running costs, and a home with higher quality insulation means less heat loss and therefore a lower overall demand. Utilising grants and incentives can also reduce the upfront costs. You could also deduct the gas daily standing charges (around £128 a year) from not using gas.

How to calculate the Payback Period

Payback Period = (Total Installation Cost - Grants) ÷ Annual Savings

Example Calculation*:
Total Installation Cost: £11,000
Boiler Upgrade Scheme (BUS) Grant: -£7,500
Net Cost: £3,500
Annual Savings: £700, including saving around £128 by removing the gas daily standing charge.
Payback Period: £3,500 ÷ £700 = 5 years

*This example is for illustration purposes only. Factors such as energy price fluctuation and energy usage may cause exact costs to vary.

Question 8

Is my home suitable for an air source heat pump?

Accepted Answer

Start with the basics: heat demand, space for the heat pump outside and the hot water cylinder inside, and your current radiators or underfloor heating. A professional heat loss calculation will confirm the right unit size and whether small upgrades will boost performance.

Insulation is key: Regardless of the system, good insulation should always be in place. Along with other measures such as quality glazing and draught proofing, quality insulation reduces heat demand, saves energy and improves comfort. Pairing your system with solar where possible can further reduce running costs and carbon.

Type of property: An air source heat pump can work well with different property types. A new build usually has strong fabric standards, making integration straightforward. An old house may need targeted improvements and emitter resizing, but it can still be suitable. Flats and terraces need careful placement for correct airflow, ensuring optimum performance. Semis and detached homes often have ample space for a heat pump outside.

Correct placement matters: The outside heat pump unit needs clear airflow, a stable base with a suitable area for condensation to drain into to prevent slippery surfaces forming in cold weather, and sensible distances from boundaries to manage noise and maintenance access. Make sure you enough space inside your property for a hot water cylinder and its components. This is often in an airing cupboard, utility room or similar.

Protecting the building and safety measures: While it’s important to have suitable clearance away from walls, adding anti-vibration measures can add further protection. Specific installation measures are required for heat pumps that use the R290 refrigerant, and so it’s important to check these carefully.

Smart controls and weather compensation help save energy day to day. Your survey will also check electrics, condensate drainage and heat pump planning permission. Many projects fall under permitted development, and therefore will not require planning permission, though there may be some exceptions. Be sure to get advice if you’re unsure.

Question 9

What size air source heat pump do I need?

Accepted Answer

Getting the size of your air source heat pump correct ensures that it delivers the output that you expect. There are several unique factors that will influence what size heat pump you’ll have, such as the level of insulation your home has, the number of rooms your home has and its layout, even the local climate. These are all taken into account when a heat loss calculation is carried out by an installer.

There are other unique aspects that will influence what size heat pump you’ll need for your property:

Insulation Quality: Poor insulation means more heat loss, which could mean that a larger, more powerful (higher kW) heat pump (potentially 1.5x larger) is needed, or improvements made to the existing insulation.

Windows & Draughts: Older, leaky windows and high ventilation can increase heat loss, therefore you may need a larger heat pump to compensate.

Hot Water Demand: Your hot water cylinder size depends on household size and usage, influencing overall demand. Remember, you will need to have a compatible air source heat pump cylinder fitted.

Radiators: Though underfloor systems tend to pair well with air source heat pumps, there might be a requirement for radiators to be modified in order to work with the lower water flow temperature that a heat pump works at.

Location: Though heat pumps are designed to work in temperatures as low as between -15°C and -25 °C, colder, exposed locations might need to have a slightly larger unit.

A heat loss calculation will accurately determine how much heat could be lost based on the specifics of your home, taking into account specific attributes of the property. This will be carried out by an expert air source heat pump installer at the first stage of the installation process.

Question 10

What are some of the misconceptions relating to air source heat pumps?

Accepted Answer

You may have gathered different information from different sources when researching air source heat pumps. Our team of experts here at Baxi have answered some of the common misconceptions of air source heat pumps that you might have come across. You can also learn more in this video.

“An air source heat pump does not warm the house like a boiler”

An ASHP works differently than a boiler. A boiler will provide short burst of extreme heat through hot radiators. An ASHP is more efficient when it runs continuously via a warm, comfortable heat. With an ASHP you will never burn your hand on a radiator, but you will feel warm throughout the whole day in your home with limited temperature drop in your home.

“An air source heat pump takes longer to heat the home”

Because heat pumps operate at lower temperatures than boilers, it may initially take longer to heat your home . However, once the desired temperature has been reached, your heat pump will maintain that temperature rather than providing short-term heat like a boiler. This means that ASHPs are more efficient to run.

“An air source heat pump won’t work well in cold weather.”

Your heat pump is designed to work in all weathers including when there is less heat for it to draw on. In fact, air source heat pumps are common in countries that have a colder climate than we experience in the UK, such as Norway and Sweden, and are capable of working effectively even when the air temperature is as low as -25°C.

Air source heat pumps have a defrost cycle. When the temperature drops and frost forms on the outside unit, sensors automatically trigger the cycle to temporarily reverse the air flow, so that frost and ice is melted away. The whole process normally only takes a few minutes with minimal disruption.

“Why might I be recommended to get a new boiler rather than an air source heat pump?”

In some instances, a heat pump might not be the most practical solution due to space limitations or as a result of property regulations. Some installers may not have the relevant qualifications or training to install a heat pump, and may suggest a boiler as a result.

Question 11

Will having an air source heat pump become mandatory?

Accepted Answer

There are currently no plans for it to become a requirement for homeowners to install an air source heat pump (ASHP). You can continue to use your current gas boiler until it reaches the end of its life.

However, two key policies have been introduced that affect new homes and aim to encourage the general adoption of ASHPs:

For New Builds: From 2025, under the Future Homes Standard, all new homes must be built with low-carbon heating systems, effectively banning fossil fuel boilers in new constructions. Heat pumps are expected to be the primary technology used to meet this standard.

For Existing Homes (Voluntary Switch): The government is promoting the voluntary adoption of heat pumps in existing homes through financial incentives, such as the Boiler Upgrade Scheme, which offers grants of up to £7,500 towards the installation cost in England and Wales.

Question 12

Does my house need to have solar or battery for air source heat pump effectiveness?

Accepted Answer

It&rsquo;s not a requirement for your home to have solar panels or batteries for your heat pump to work, however combining it with these technologies may lead to better energy efficiency, bringing down your environmental impact and leading to lower running costs.

Question 13

Are there any incentives for having an air source heat pump fitted?

Accepted Answer

Depending on your bank and mortgage provider, you may be able to access incentives and discounts for having an air source heat pump fitted, including cashback and lower interest rates. Some also have their own schemes for customers depending on eligibility.

As well as potential discounts from mortgage providers, you may be eligible to get a discount from government grants, such as the Boiler Upgrade Scheme, which can provide eligible homeowners a discount of up to £7 500 to help with the upfront costs of a heat pump.

Question 14

Where do the air source heat pump and cylinder need to go?

Accepted Answer

You will need to have a cylinder installed with your heat pump in order to use it for your hot water. This will need to be a specialised cylinder that is compatible with the lower temperatures that air source heat pumps operate at. This means that you will not be able to use a cylinder from your previous boiler system.

An air source heat pump is installed outdoors, ensuring there is enough space around it for air to flow across the fan unobstructed. It should also be placed on a flat, stable surface, and we also recommend gravel for condensate to safely drain into and minimise the risk of a slippery surface forming due to condensate that naturally forms during its operation. Your installer will discuss the most suitable place for your heat pump to be positioned so that it can work to its full potential.

Considerations will need to be made so that the cylinder is not too far away from the heat pump, which can cause heat to be lost through the pipework, and the heat pump itself will need to be suitably placed so that it complies with specific regulations for noise levels and safety.

Question 15

Where should I have my heat pump cylinder fitted? Do they need to be close together?

Accepted Answer

Your heat pump and cylinder will need to be situated fairly close to each other in order to prevent heat being lost from the pipework that connects the two of them together. Pipework will also be insulated to further help retain heat as it travels from the outside heat pump to the inside cylinder.

For example, having the heat pump in the rear garden and the cylinder in the front of the property could lead to greater heat loss due to the distance the heat has to travel, resulting in lower efficiency.

Question 16

Do I need to replace my windows for an air source heat pump installation?

Accepted Answer

It&rsquo;s not a requirement to have new windows fitted when having an air source heat pump fitted, however upgrading to double or even triple glazing could help maintain its efficiency by preventing heat loss, which would mean that your heat pump would have to work harder to compensate.

Question 17

Will I save money with an air source heat pump? How much would I be able to save? Is it worth it in the long run?

Accepted Answer

Though the initial set up costs of getting an ASHP installed may appear high, grants such as the Boiler Upgrade Scheme are available for eligible households that can reduce these expenses. You can check your eligibility via GOV UK: www.gov.uk/apply-boiler-upgrade-scheme/check-if-youre-eligible.

Heat pumps are designed to be more efficient than gas boilers – typically producing 3-4 units of heat for every unit of electricity used. When used with high quality insulation, it is possible to benefit from additional long term cost savings.

Question 18

How much will having an air source heat pump reduce my emissions?

Accepted Answer

It has been suggested by The Renewable Energy Hub that the UK could save around 54 million tonnes of CO2 a year if every home switched to a heat pump, bringing down the country’s entire emissions output of 330 million tonnes by 16%. With advancements continuously being made to the UK’s electricity grid to improve its efficiency, having an air source heat pump fitted may become commonplace across the country in the years to come.

Question 19

How long does an air source heat pump last compared to a boiler?

Accepted Answer

An air source heat pump that has been well-maintained and serviced regularly can perform for around 20 years. This exceeds the lifespan of a boiler, which is typically only around 10 to 15 years.

At Baxi, a service for your air source heat pump ensures that your warranty remains valid. It also helps to keep all key components of your heat pump working at an optimal level and identifies any potential issues before they can develop.

Question 20

Where else can I learn more about air source heat pumps and other technologies?

Accepted Answer

There is a wealth of information out there to help you understand air source heat pumps. At Baxi, we have a collection of blogs and FAQs and have an expert team of installers to support you should you need additional information. Our videos can also give you greater insight into how your heat pump works.

You can also learn about ASHPs from other sources, such as the Eco Experts and the Energy Saving Trust.

Air Source Heat Pump Comprehensive Guide